The present invention relates to a scrub washing apparatus and scrub washing method for washing a substrate such as a semiconductor wafer and an LCD glass substrate.
In manufacturing steps of semiconductor devises, a single-processing substrate washing system is used for removing contaminants, such as particles, organic compounds, and metal ions, attached to a surface of a semiconductor wafer. The single-processing substrate washing system has a scrub washing apparatus for scrubbing away attached materials (contaminants) from the surface of the wafer by brining a brush or a sponge (hereinafter referred to as xe2x80x9cscrub memberxe2x80x9d) into contact with the wafer in rotation.
The scrub washing apparatus has a swingable horizontal arm, a vertical output shaft arranged at a tip portion of the horizontal arm, a scrub member directly or indirectly supported by the vertical output shaft, a rotation drive means for driving the rotation of the scrub member together with the vertical output shaft, and a press means for pressing the scrub member downward together with the vertical output shaft. A contact pressure of the scrub member to the substrate (hereinafter referred to as xe2x80x9cscrub contact pressurexe2x80x9d) corresponds to a total force of a press force given to the scrub member by the press means and a weight of the scrub member itself. The surface of the substrate is desirably washed by properly controlling conditions including the scrub contact pressure, a rotation speed of the scrub member, a moving speed of the scrub member, and a rotation speed of the substrate, in accordance with the surface state of the substrate.
Such a scrub apparatus is disclosed in Japanese Patent Application KOKAI publication Nos. 8-141518, 8-141519. In these conventional apparatuses, an expandable bellows mechanism and an air cylinder mechanism are employed as the press means. For example, in the bellows mechanism described in Japanese Patent Application KOKAI 8-141518, the press force is applied to the vertical output shaft by expanding and contracting of the bellows fitted at an upper end of the vertical output shaft. In the air cylinder mechanism, the press force is applied from the cylinder to the vertical output shaft by protruding or retracting a piston rod attached to an upper end of the vertical output shaft. However, in the conventional apparatuses, if a rub resistance between the vertical output shaft and a bearing is changed, the press force may not be desirably transmitted to the scrub member. Since a belt mechanism is used as a rotation drive mean in the conventional apparatus, the rotation force may not be desirably transmitted to the scrub member because the tension of the belt varies. Furthermore, a driving force transmission mechanism of the conventional apparatus is complicated in structure since numerous mechanical elements such as a belt, a pulley, a bellows, an air cylinder, and a bearing, are assembled, resulting in generation of particles in a non-negligible amount. The generated particles are attached to the substrate, degrading the cleanliness of the substrate surface.
An object of the present invention is to provide a scrub washing apparatus and method capable of transmitting a desired press force and a rotation driving force to a scrub member without fail and generating few amount of particles.
According to the present invention, there is provided a scrub washing apparatus comprising:
a mounting table for holding a substrate to be processed substantially horizontally;
a washing liquid supply mechanism for supplying a washing liquid to the substrate mounted on the mounting table;
an arm vertically and horizontally movably supported;
an output shaft provided at the arm;
a scrub member connected directly or indirectly to the output shaft, for scrubbing the substrate on the mounting table in contact therewith;
a press mechanism moving the scrub member together with the output shaft, for pressing the scrub member against the substrate on the mounting table; and
a rotation drive me chanism provided above the press mechanism at a position where the rotation drive mechanism is capable of being engaged with a the output shaft, for directly rotating the scrub member by engaging with the output shaft.
In this case, the o utpu t shaft has an upper portion extending upward from the press mechanism, a driven engage member attached to the upper portion, and a lower portion extending downward from the press mechanism and connected to the scrub member; and
the rotation drive mechanism has a rotation drive shaft extending downward and a drive engage member attached to a lower end of the rotation drive shaft.
The apparatus further comprises a liftable moving mechanism for moving the output shaft up and down to the press mechanism. The liftable moving mechanism moves up the output shaft to engage the driven engage member with the drive engage member, thereby transmitting the rotation drive force from the rotation driving mechanism to the output shaft.
The drive engage member preferably has
a first connection board connected to the rotation drive shaft;
a horizontal support shaft attached to the first connection board; and
a pair of rollers supported by the horizontal support shaft.
The driven engage member preferably has
a second connection board connected to the output shaft;
a plurality of vertical projections respectively standing at corners of the second connection board; and
depressed portions formed between two adjacent projections.
The output shaft is moved up by the liftable moving mechanism to engage the depressed portions with the pair of rollers, thereby transmitting rotation driving force from the rotation drive mechanism to the output shaft.
The driven engage member has a plurality of projections extending in direction of the rotation drive shaft. Depressed portions are formed between two adjacent projections. The drive engage member is engaged with the depressed portions.
According to the present invention, there is provided a scrub washing method of scrubbing a substrate with a scrub member while a washing liquid is supplied to the substrate by transmitting a press force and a rotation driving force to the scrub member by means of an output shaft and a rotation drive shaft, which comprises the steps of:
(a) setting a scrub contact pressure when the substrate is scrubbed with the scrub member, the output shaft being engaged with the rotation drive shaft and arranged on an extension line of the rotation drive shaft;
(b) mounting the substrate on a mounting table;
(c) moving the scrub member above the substrate mounted on the mounting table;
(d) moving down the scrub member together with the output shaft;
(e) transmitting a rotation drive force to the output shaft from the rotation drive shaft to rotate the scrub member; and
(f) adjusting the pressing force of the scrub member to the substrate at the scrub contact pressure set at the step (a).
In the conventional apparatus, since the rotation drive shaft is located at a distance from the output shaft, a rotation driving force is transmitted to the output shaft from the rotation drive shaft by way of a belt and a pulley. Since the rotation driving force is transmitted indirectly, the output shaft is likely to be affected by various external disturbances (change in tension of a belt), with the result that up-and-down movement and rotation movement of the output shaft become unstable.
In contrast, in the apparatus of the present invention, since the rotation drive shaft is located immediately above the output shaft, the rotation driving force is transmitted directly from the rotation drive shaft to the output shaft. Since the rotation driving force is directly transmitted as described, the output shaft is not affected by the external disturbances, with the result that the up-and-down movement and the rotation movement of the output shaft become stable.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.